Thai anti-government protesters abandoned efforts to block candidates from signing up for a February election on Tuesday but vowed to hound Prime MinisterYingluck Shinawatra and thwart a poll she is expected to win.

The protesters want Thailand's fragile democracy to be suspended, fearing the February 2 election would only entrench the power of Yingluck's billionaire family, which is hugely popular among the rural poor of the populous north and northeast.

At their peak, rallies seeking to overthrow Yingluck and install an appointed government have attracted more than 200,000 people, with strong backing from Bangkok's middle classes.

Many among the Bangkok elite believe rural voters have been bought off by populist policies that have fuelled government graft. Thirty-five parties have signed up for the poll, despite attempts by protesters to stop them when registrations opened at a Bangkok sports stadium on Monday.

Protest leader Suthep Thaugsuban, a former deputy premier famed for fiery speeches, called off the blockade on Tuesday but promised to ramp up the campaign and chase Yingluck from office.

Yingluck, the sister of self-exiled former premier Thaksin Shinawatra, called a snap poll two weeks ago to try to deflate the protests. The noisy but mainly peaceful protests are driven by anger over Thaksin's influence over his sister's government.

"If Yingluck doesn't resign or stays until February 2, we will block all parts of Bangkok and will not allow a single Bangkokian to cast a vote," Suthep told supporters.

"If you see Yingluck, no matter where she is, please call us, or post it on social media and we'll send our mobile units to chase her everywhere," he said.

Yingluck has been in her Puea Thai Party's northern strongholds courting support while her credibility is attacked in Bangkok. She has been on the road for six of the past eight days and on Tuesday extended her trip until the New Year.

The election has been made more uncertain by a boycott by the main opposition Democrat Party, which draws its support from Bangkok and the south, the same base as Suthep's group.

Strain on economy

The Democrats have not won an election in 21 years but are backed by a powerful Bangkok establishment of generals, bureaucrats and influential conservatives with deep disdain for Thaksin, a man they say bent laws to enrich his family and cemented his power through cronyism and political patronage.

The latest round of turmoil in the eight-year crisis has taken its toll on the economy, Southeast Asia's second biggest, and has affected tourism. It has delayed plans to spend $65 billion on infrastructure, which the government had hoped would offset struggling exports.

The baht fell to an almost four-year low against the US dollar low on Monday. A central bank official said on Tuesday the bank had moved to smooth excessive volatility in the currency but gave no details.

Uncertainty surrounds whether the election will actually take place or if protests, which so far have failed to stop the government from working, will turn violent in the hope a coup-prone military with little love for Thaksin would intervene.

The military, however, has vowed to stay neutral and has offered to help the polls run smoothly. The Election Commission reiterated on Tuesday the election would go ahead as planned.

The protests seemed unlikely a few months ago, when Thaksin's enemies appeared content to tolerate the government. However, Puea Thai made a costly blunder in November, when the party tried to force an amnesty bill through parliament that would have nullified Thaksin's 2008 graft conviction and allowed him to return from Dubai.

The bill was scrapped but it struck a nerve with many Thais who oppose the influence of his family and friends.